Tube reducing and elongating apparatus

ABSTRACT

TUBE REDUCING AND ELONGATING APPARATUS OF THE &#34;DIESCHER&#34; TYPE HAVING A MAIN FRAME ROTATABLY SUPPORTING OPPOSED, BARREL-SHAPED, TUBE WORKING ROLLS WHICH FORM A PASS FOR THE TUBE AND HAVING OPPOSED, TUBE-CONFINING DISKS AT THE WORKING ROLL PASS ROTATABLY MOUNTED IN RESPECTIVE SUB-FRAMES WHICH ARE EASILY REMOVABLE FROM THE MAIN FRAME FOR READY REPAIR OR REPLACEMENT OF THE DISKS. IN ADDITION, THE MANDREL NORMALLY DISPOSED WITHIN THE TUBE BEING ELONGATED IS ROTATED THEREWITH AT THE SAME SPEED AND IN THE SAME DIRECTION AS THE THEORETICAL ROTATIONAL SPEED IMPARTED TO THE TUBE BY THE WORKING ROLLS AND THE MANDREL IS SIMULTANEOUSLY ADVANCED WITH THE TUBE AT THE SAME SPEED AT WHICH IT EXITS FROM THE PASS FORMED BY THE WORKING ROLLS AND THE DISKS.

March 2, 1971 TH Q 3,566,653 Y TUBE REDUCING AND ELONGATING APPARATUSFiled NOV. 15, 1968 6 Sheets-Sheet 1 March 2, 1971 v E. a. UNRATH3,566,653

TUBE REDUCING AND ELONGATING APPARATUS Filed Nov. 15, 1968 6Sheets-Sheet 2 g Z O O k 9 m3 R4 I l INVENTOR.

Q ERNEST GUNRATH BY flaw la/fizz? A T TOPNzff5 E. G. UNRATH TUBEREDUCING AND ELONGATING APPARATUS I March 2, 1971 6 Sheets-Sheet 4 FiledNOV. 15, 1968 I .m 6 MA Z E March 2, 1971 E, UNRATH 7 3,566,653

TUBE REDUCING AlfJD ELONGATING APPARATUS Filed NOV. 15, 1968 r 6Sheets-Sheet 5 &

g a 53 Z 2% 4M Q 4 24/, V14

INVENTOR. ERNEsT G. UNRATH March 2, 1971 I UNRATH 3,566,653

I I TUBE REDUCING AND ELONGATING APPARATUS Filed Nov. 15, 1968 r 6Sheets-Sheet 6 INVENTOR. ERNEST GUNRATH A frofrways United States PatentOffice 3,566,653 Patented Mar. 2, 1971 3,566,653 TUBE REDUCING ANDELONGATING APPARATUS Ernest G. Unrath, Pittsburgh, Pa., assignor to WeanIndustries, Inc., Youngstown, Ohio Filed Nov. 15, 1968, Ser. No. 776,124Int. Cl. B2111 19/06, 31/12 US. Cl. 7296 11 Claims ABSTRACT OF THEDISCLOSURE Tube reducing and elongating apparatus of the Diescher typehaving a main frame rotatably supporting opposed, barrel-shaped, tubeworking rolls which form a pass for the tube and having opposed,tube-confining disks at the working roll pass rotatably mounted inrespective sub-frames which are easily removable from the main frame forready repair or replacement of the disks.

In addition, the mandrel normally disposed within the tube beingelongated is rotated therewith at the same speed and in the samedirection as the theoretical rotational speed imparted to the tube bythe working rolls and the mandrel is simultaneously advanced with thetube at the same speed at which it exits from the pass formed by theworking rolls and the disks.

Apparatus for reducing and elongating tubular stock and provided with apair of opposed, oppositely inclined rotatable rolls forming a passthrough which the stock advances and also provided with opposedrotatable disks at the roll pass for confining the stock therebetweenhas long been known. Such apparatus is disclosed, for example, inLetters Patent 1,870,209, issued Aug. 2, 1932, to Samuel E. Diescher andsuch apparatus is frequently known as a Diescher type mill.

While such apparatus has been generally satisfactory, it has not beenwidely used, despite the high quality of the tubing produced thereby,because of three principal factors: Firstly, productive output has beenslower than that of other tube reducing and elongating apparatus.Secondly, maintenance has been costly because of the productive timelost in maintaining and replacing the disks which, by the very nature ofthe apparatus, are subject to relatively rapid wear. Thirdly, themanufacture of some of the larger tube sizes has been impractical.

SUMMARY OF THE INVENTION While the use of modern disk materials andclose control of the material of the tubing stock can reduce thefrequency of disk maintenance and replacement, disk Wear remainsrelatively rapid. It is, therefore, an object of the present inventionto reduce the undesirable consequence of rapid disk wear by making diskremoval and replacement far easier than before.

The foregoing object is accomplished by rotatably mounting each disk inits own sub-frame which is easily removed from and replaced in itsnormal working position. Thus, when the working faces of the disks needattention, such disks along with their sub-frames may readily be removedand replaced with sub-frames mounting new disks or disks which havepreviously been put in working condition. The apparatus may then beplaced in production once again while the worn disks are leisurelyremoved from their sub-frame, refinished or replaced as necessary, andthen replaced in their sub-frames for subsequent future installation inthe apparatus.

In addition to rendering disk replacement far easier and quicker thanbefore, the present invention contemplates increased productivity,without loss of quality, by a novel method of rotation and advancementof the mandrel disposed within that tube being elongated. In apparatusof the present type, rotation of the tube and its rate of advancementthrough the pass formed by the working rolls and the tube-confiningdisks is a combined function of the peripheral speed of the workingrolls, their angle of inclination, the exterior diameter of the tubebeing elongated, and the peripheral speed of the tubeconfining disks.'Ihe mandrel, however, because of its mass, heretofore tended to retardboth rotation of the tube and its longitudinal advance through the pass.Thus, production has suffered, especially where the mandrel has beenlong in length (for the manufacture of long tube sections) and/or wherethe mandrel has been large in diameter (for manufacture of large insidediameter tube sections). The improved method, therefore, lies ineliminating the retarding effect of the mandrel by rotating the latterat no less than the rotational speed imparted to the tube by workingrolls and by advancing the mandrel at a speed no less than thelongitudinal speed of the tube as it exits from the pass provided by theworking rolls and the tube-confining disks.

These and other advantages of the present invention will readily becomeapparent from a study of the following description and from the appendeddrawings, and in these drawings:

DRAWING DESCRIPTION FIG. 1 is a side elevational view, devoid ofsupporting structure, of the working rolls and disks used in apparatusof the present invention.

FIG. 2 is an end elevational view of the parts seen in FIG. 1 andgenerally corresponding to the line 22 thereof,

FIG. 3 is a fragmentary, generally diagrammatic side elevational view ofapparatus embodying the present invention,

FIG. 4 is a view like FIG. 1, but with certain parts omitted,

FIG. 5 is a transverse sectional view, generally corresponding to theline 55 of FIG. 1, but showing supporting structure for the rolls andthe disks,

FIG. 6 is a fragmentary sectional view generally corresponding to theline 6-6 of FIG. 5,

FIG. 7 is a view similar to FIG. 5 but showing certain parts in otherpositions,

FIG. 8 is a side elevational view of a sub-assembly,

FIG. 9 is an exploded view of the sub-assembly seen in FIG. 8 and withcertain parts shown in section to better illustrate the underlyingstructure,

FIG. 10 is a fragmentary enlarged view, partially in section, of amodified sub-assembly, and

FIG. 11 is a view similar to FIG. 6 but of the modification seen in FIG.10.

DETAILED DESCRIPTION With reference to FIGS. 1 and 2, a pair ofbarrelshaped, working rolls 10 are disposed in adjoining relation todefine a pass therebetween for the tube T to be elon- 3 gated. Rolls aredisposed in opposed relation relative to the tube and their axes areinclined in opposite directions with respect to the tube axis, as bestseen in FIG. 1 for reasons to appear. Although not shown, rolls 10 areadapted to be simultaneously rotated in the directions indicated by anysuitable means.

To prevent transverse movement of the tube from between the rolls 10,disks 11 are disposed in diametrically opposed relation for engagementwith opposite sides of the tube being elongated at the pass provided bythe rolls and are adapted to be rotated in the directions indicated byany suitable arrangement. Preferably, the peripheries of disks 11 areconfigurated for conformity with the exterior of the tube beingelongated.

Assuming that the spacing between the rolls 10 is less than thetransverse size of the entering tube and tha the rolls and the disks arebeing rotated as indicated, a tube T will be fed from left to rightbetween the rolls 10. Since the latter are inclined in oppositedirections, they will not only impart rotation to the tube, but willalso draw the tube between the rolls and move it axially to the right.Since the spacing between the rolls is less than the transverse size ofthe entering tube, such tube will exit from the pass reduced intransverse size and elongated in length. In order to establish adefinite inside diameter and a definite wall thickness of the exitingtube, a suitably sized mandrel 12 is disposed within the tube prior topassage thereof between the rolls 10, such mandrel rotating and movingaxially with the tube as it passes through the rolls.

Turning now to FIG. 3, it is to be noted that the rolls 10 are rotatablymounted in a suitable housing or frame 13 and in the position of partsshown, a tube entry table 14 is disposed to the left of frame 13 while atube exit table 15 is disposed to the right thereof. For supporting therotating tube T, the exit table may be provided with the usual tubesupporting rollers 16 or the like; however, at the entry table 14, aconveyor 17 mounts a series of V-blocks 18 in which the entering tube iscradled.

Slidably mounted on the entry table 14 in any convenient manner is acarriage 19 having a rotably mounted head 20 engageable with thepreviously mentioned mandrel 12. A suitable drive motor 190 elfectsrotation of head 20 and consequent rotation of the mandrel 12 in amanner later to appear. The means presently provided for advancing thecarriage 19 and the engaged mandrel to the right may comprise a link 21connecting the carriage to the conveyor 17. Upon movement of conveyor 17to the right as by a drive motor 22, the V-blocks cradling the enteringtube will feed the latter to the right into the pass provided by theworking rolls 10 and the tube-confining disks 11 while the carriage 19,moving with the conveyor, will feed the mandrel 12 to the right with thetube. As will later appear, it is an important feature of the presentinvention that since the V-blocks 18 have only frictional engagementwith the tube portion resting thereon, such blocks may move to the rightat a rate of movement greater than the axial rate of movement to theright of the supported tube portion into the previously mentioned,working roll pass.

With reference now to FIG. 4 wherein but a single roll 10, the disks 11and the tube T are shown, if it be assumed that the axes of rolls 10 aredisposed at, for example, an angle of six degrees with the axis of thetube and if it further be assumed that rolls 10 are rotated at aperipheral speed of, say 1000 feet per minute and disregarding for themoment the disks 11, the tube will in theory be rotated by the rolls atthe same peripheral speed as that of the rolls and a resultant axialcomponent will be developed which will in theory axially shift the tubethrough the pass provided by the rolls 10 at a rate of 105 feet perminute. In normal practice, however, the disks 11 are rotated in thedirections indicated and at respective peripheral speeds considerably inexcess of the rate of tube advance caused by the rolls and thus the tubeis assisted in its passage between the rolls and the disks. By

4 way of example, the over-driven disks 11 may cause the tube to advancebeyond the pass at a rate of of the theoretical rate resulting fromoperation of the working rolls alone. In the present example, therefore,the tube would be discharged from the pass at a speed of about feet perminute.

While disks 11 can be driven at even greater speeds to still furtherincrease tube output speed, the increased burnish'ng action may provedetrimental to the tube outer surface and, disk wear increases markedlyto a point where the increase in tube output speed is offset by rapiddisk wear.

It has been found that if the mandrel 12 disposed within the tube isrotated at a speed corresponding to the theoretical speed of rotationimparted by the rolls 10 and, if the mandrel is at the same time shiftedaxially in the same direction as the tube and at a speed correspondingto the speed at which the tube is discharged from the pass provided bythe roll-disk pass, materially faster and higher quality production willresult. By so rotating and advancing the mandrel, its drag upon the tubeis eliminated thus making possible throughput tube efficiencies ofapproximately as against the prior art 135% efficiency where the mandrelis allowed to float with the rotating and advancing tube in response tofriction developed therebetween. At the same time, the peripheral speedof disks 11 may be reduced somewhat thus improving their wear rate.

It is to be understood that since the tube is elongated in its passagethrough the roll-disk pass, the tube will exit from the pass at a speedgreater than the speed at which it enters the same. This results becausethe squeezing action of the pass on the tube causes metal flow in areverse direction to tube movement and this flow causes a reduction inthe rate of tube advance into the pass. Now, since the mandrel is beingadvanced by the carriage 19 attached to the conveyor 17 at a rate atleast equal to tube exit speed, it follows that the conveyor must travelat a rate in excess of the rate of advance of the tube into the rolldiskpass. It is for this reason important that the conveyor have onlyfrictional engagement with the pass-entering tube portion to permit suchdifferential speed.

While it has been disclosed that the mandrel is rotated at a speed equalto the rotational speed imparted to the tube by the working rolls andthe mandrel is advanced at a speed equal to the speed at which the tubeexits from the roll-disk pass, it is to be understood that the presentinvention contemplates both rotation of the mandrel and advance thereofat even greater speed to still further increase tube throughput speed.

Referring now to FIG. 5, the rolls 10 are rotatably mounted inrespective chocks 23 which are slidable along ways 24, formed in thepreviously mentioned housing or frame 13, toward and away from eachother to vary the spacing between the rolls. The positions of chocks 23along the ways 24 may be adjusted by any convenient means and, as hereindisclosed, screw threaded rods 25 are rotatably anchored in respectivechocks and pass through threaded apertures in respective bridgingmembers 26 removably secured to the frame 13.

Disks 11 are also movable toward and away from each other to vary thespacing therebetween and since the structures mounting these disks aresimilar, that mounting the upper disk 11 will only be described indetail. Still referring to FIG. 5 but also referring to FIGS. 6 and 7,upper disk 11 is carried by a sub-frame 27 providing spaced arms 28between which the disk is disposed. The free ends of arms 28 provideseats 29 for receiving respective bearings 30 (only one of which can beseen in FIG. 5) mounted in axially spaced relation on a shaft 31. Disk11, of course, is mounted on the shaft 31 intermediate the bearings 30in a manner later to be described in detail. Bearing seats 29 are splitlongitudinally along the axis of shaft 31 to provide cap portions 32removably secured in position by suitable fastening members 33. Shaft 31is preferably elongated at 34 for removable connection to a suitabledrive shaft which, however, is not shown in the drawings.

As herein shown, the central portion 35 of shaft 61 has a diametergreater than the outside diameter of bearing for a purpose to appear andis further provided with a fixed shoulder 36 for abutting and axiallylocating the disk 11. The latter has a bore 37 closely fitting withshaft portion and an internally threaded locking ring 38 is threadedupon shaft portion 35 to removably retain the disk assembled with theshaft. Although not shown, a suitable key or spline arrangement may beprovided to insure against rotation between the shaft and the disk.

Means are provided for guiding vertical movement of sub-frame 27 and asbest shown in FIG. 6, frame 1 3 is provided with an enlarged opening 39for receiving the sub-frame, and pairs of opposed ribs 40 closely fitwithin respective slots 41 formed in the sub-frame and which extendlongitudinally of respective sub-frame legs 28. In a manner similar tothe chocks 23, the vertical position of sub-frame 27 may be adjusted bya screw threaded rod 42 which is rotatably anchored to the subframe andpasses through a threaded aperture in a bridging member 43 removablysecured to the frame 13.

Since the sub-frame mounting the lower disk 11 is identical to the upperone hereinabove described, corresponding parts are identified with thesame reference characters as before but with the suffix a added. Forreasons to appear, bridging member 4361 is formed integrally with themain frame 13 rather than being separable therefrom as is member 43.Moreover, threaded rod 42a preferably is not rotatably anchored to thesubframe 27a but merely bears against the lower end thereof.

As hereinabove mentioned, disks 11 are prone to wear since they aregenerally driven as a rotational speed in excess of the speed of axialmovement of the tube being elongated. Accordingly, it is necessary torestore the working peripheries of such disks at relatively frequentintervals and to replace them with new disks when they are no longerserviceable.

If only the upper disk need be serviced, the drive shaft (not shown)normally connected to the shaft 31 will be disconnected therefrom andthe bolts securing the bridging member 43 will be removed to permit theentire sub-frame 27 with its disk to be raised along the ribs 40 untilsuch sub-frame assembly is free of the main frame 13. A previouslyprepared, identical sub-frame assembly will next to lowered in place,properly secured in position and the drive shaft reconnected to theshaft 31 of such identical assembly whereupon production may be resumed.

The worn disk 11 may now leisurely be removed from its subframe bylateral movement of the shaft (see FIG. 9). With the shaft and diskremoved as a unit from the sub-frame, the disk may readily be re-groundto restore its working periphery.

If, however, the disk 11 must be removed from the shaft for replacement,it is unnecessary to disturb either of the shaft bearings 30. In suchevent, the locking ring 38 will be unscrewed from the shaft and thendisassembled therefrom by axial movement to the left, in the position ofparts seen in FIG. 9. With the ring 38 removed, removal of the disk 11will follow in the same manner. Removal of the ring and the disk fromthe shaft as above described is made possible by reason that theexternal diameter of the left-hand bearing 30 is shown at 44 to be lessthan the diameter shown at 45 of the disk bore 37. With the new diskinstalled on and secured to the shaft 31, the latter will be reassembledwith its sub-frame by a reversal of the above-described opera tions andthe now completed sub-frame assembly may be stored until it is to besubstituted for the assembly then in use.

Although removal and replacement of only the upper disk 11 has beendescribed it is much more common to replace both disks at the same timein view of the fact that both will wear at about the same rate.Accordingly, following removal of the sub-frame 27 from the main frame13 as previously detailed, the chocks 23 mounting the rolls 10 will beshifted from their normal positions seen in FIG. 5 to the widelyspaced-apart positions seen in FIG. 7. With the chocks 23 thusseparated, sub-frame 27a may be raised along its ribs 40a, passedbetween the rolls 10, and removed from the main frame. A previouslyprepared sub-frame assembly may now be substituted for the one justremoved and following return of the chocks 23 to their normal positionsand installation of the upper sub-frame assembly, production may beresumed. The previously removed lower subframe assembly may now bedisassembled for necessary repair or replacement of parts as heretoforedescribed with respect to the upper sub-frame and when re-assembled, maybe stored for subsequent reuse.

To facilitate removal of the lower sub-frame assembly from the mainframe as above described, the subframe may be dimensioned to pass freelybetween rather than slidably along the main frame ribs 40 whichcooperate with the upper sub-frame. Such construction, of course, wouldrequire the main frame ribs 40a to be dimensioned to slidably fit withthe lower sub-frame.

In the embodiment of the invention seen in FIGS. 10 and 11 whereincorresponding parts are identified by the same reference characters asbefore but with the suffix .1 added, the right-hand bearing 30.1 is notmounted directly in the 'seat 29.1 of the sub-assembly leg 28.1 butinstead is mounted in a sleeve 46 which is in turn disposed in the legseat 29.1. Sleeve 46, however, is not tightly gripped in the leg seat29.1 but rather is slidable axially therein for a purpose to appear.

Removably secured within the right-hand end of sleeve 46 by any suitablemeans, as by threading the parts together, is a plate 47 to which isanchored an adjustment screw 48. Secured to the leg 28.1 in concentricrelation with the sleeve 46 is a housing 49 rotatably mounting a wormgear 50 having threaded engagement with the screw 48. A worm 51 isengaged with the worm gear 50 and has operative connection with anadjusting shaft 52 whereby rotation of the latter effects rotation ofthe worm and consequent rotation of the worm gear. Although not shown,the bearing 30.1 in the other sub-assembly leg 28.1 may be axiallyslidable within its seat in the leg to provide for axial movement of theshaft 31.1 as will next appear.

With the construction seen in FIG. 10, rotation of the worm gear 50 willeffect axial movement of the screw 48 and consequent axial movement ofthe shaft 31.1 and the attached disk 11.1. This arrangement provides ahighly desirable axial adjustment of the disk 11.1 and, while only anupper sub-frame assembly 27.1 has been described, it will be clear thatthe lower sub-frame assembly may be similarly constructed for axialadjustment of the lower disk.

With reference now to FIG. 11, means are also provided for adjusting theposition of the upper disk 11.1 relative to the working rolls and in adirection along the path of stock travel. As herein disclosed, the mainframe ribs 40.1, instead of being integral as seen in FIG. 6, are formedof separate pieces which include laminations or shims 53. Capscrews 54retain respective rib pieces in assembled relation. When adjustment ofthe upper disk along the path of stock travel is desired, shims 53 onone side of the sub-frame assembly 27.1 may be removed and installed onthe opposite side of such assembly. As will be clear, this will notchange the spacing between opposed ribs but will shift such spacingthereby re-positioning the sub-frame and its disk. The transferaforesaid of the shims 53, of course, will be effected after thesub-frame has been removed from the main frame and, while shimadjustment of only the upper sub-frame has been disclosed, similarstructure may be provided for adjusting the lower sub-frame.

I claim:

1. Apparatus for elongating tubular stock and providing a pair ofopposed, oppositely inclined rotatable rolls forming a pass throughwhich the tubular stock advances and further providing a pair ofopposed, rotatable disks at said roll pass for confining the stocktherebetween, the improvement comprising a main frame rotatablysupporting said rolls,

and a pair of sub-frame assemblies each rotatably mounting respectivedisk and each removably secured to said main frame to provide, withminimum loss of production time, for ready disassembly of said sub-frameassemblies therefrom and ready assembly of other sub-frame assembliestherwith, when said disks must be refaced or replaced.

2. The construction of claim 1 wherein each disk is mounted on asupporting shaft which is journaled in a respective sub-frame assembly,

and wherein adjustment means is mounted on each sub-frame assembly andeach has connection with respective shafts aforesaid for axiallyshifting the latter and the disks mounted thereon.

3. The construction of claim 1 wherein said main frame and respectivesub-frame assemblies are provided with cooperable, interengaging guidemeans along which said sub-frame assemblies are shiftable toward andaway from assembled relation with said main frame.

4. The construction of claim 3 wherein one of said main frame and one ofsaid sub-frame assemblies pro vides elongated ribs in opposed relationforming a part of said guide means,

and wherein a portion of one of said ribs is transferable to the otherof said ribs to shift the path of movement of said sub-frame and thusvary the position of the disk carried thereby in a directionlongitudinally of the path of stock travel without effecting the spacingbetween said ribs.

5. The construction of claim 1 wherein said disks are respectivelydisposed above and below the line of stock travel,

wherein said rolls are disposed on respective sides of the line of stocktravel,

and wherein said rolls are mounted for movement away from each other anamount sufficient to provide for passage between said rolls of thesub-frame assembly mounting the lowermost of said disks.

6. The construction of claim 1 wherein a sub-frame assembly aforesaidprovides a pair of legs in spaced, sideby-side relation,

wherein a shaft extends transversely of and between said legs,

wherein a disk aforesaid is mounted on said shaft between said legs,

wherein bearing assemblies are secured to said shaft and are interposedbetween the latter and respective legs aforesaid, wherein retainingmeans removably retain said bearings assembled with respective legs andsaid retaining means being removable to provide for assembly anddisassembly of said shaft with said legs in a direction longitudinallyof the latter, wherein said shaft provides a seat intermediate saidbearing assemblies for mounting said disk,

wherein said disk is centrally apertured to pass one end of said shaftduring assembly and disassembly operations therewith,

and wherein said disk aperture is of a size to pass the bearing assemblyat said shaft one end to provide for removal of said disk from saidshaft without disturbing said shaft bearings.

7. Apparatus for elongating tubular stock and providing a pair ofopposed, oppositely inclined rotatable rolls forming a pass throughwhich the tubular stock advances, and further providing a pair ofopposed, rotatable disks at said roll pass for confining the stocktherebetween, the improvement comprising:

a frame having horizontal guide surfaces on opposite sides of said pass,

a bearing for each roll slidable along a respective horizontal guidesurface toward and away from said pass,

said frame also having vertical guide surfaces above and below saidpass,

a bearing for each disk, slidable along a respective vertical guidesurface toward and away from said pass, the bearing for the upper diskbeing movable upwardly along the upper vertical guide surface todisassembled relation with said frame,

the upper vertical guide surface being in vertical alignment with thelower vertical guide surface but being constructed and arranged so thatafter the bearing for the upper disk has been disassembled from saidframe, the bearing for the lower disk may be. moved upwardly along itsvertical guide surface, upwardly through the pass area and upwardly andthrough said upper vertical guide surface to disassembled relation withsaid frame,

said roll bearings being slidable away from said pass an amountsufiicient to permit said lower bearing and its disk to move verticallythrough the pass area.

8. Apparatus for elongating tubular stock and providing a pair ofopposed, oppositely inclined rolls forming a pass through which thetubular stock advances, and further providing a pair of opposed,rotatable disks at said roll pass for confining the stock therebetween,the improvement comprising:

a frame having horizontal guide surfaces on opposite sides of said pass,

a bearing for each roll, slidable along a respective horizontal guidesurface toward and away from said pass,

said frame also having a pair of spaced vertical guide surfaces aboveand below said pass,

a bearing for each disk, slidable along a respective pair of verticalguide surfaces toward and away from said pass, the bearing for the upperdisk being movable upwardly along the upper pair of vertical guidesurfaces to disassembled relation with said frame,

the upper and lower pairs of vertical guide surfaces being in verticalalignment, with the spacing between the lower pair of guide surfaces andthe bearing confined therebetween being sufficiently less than thespacing between the upper pair of guide surfaces and the bearingconfined therebetween, respectively, so that after the bearing for theupper disc has been disassembled from the frame, the bearing for thelower disk may be moved upwardly along its pair of lower vertical guidesurfaces, upwardly through the pass area, and upwardly between said pairof upper guide surfaces to disassembled relation with said frame,

said roll bearings being slidable away from said pass an amountsufiicient to permit said lower bearing and its disk to move verticallythrough the pass area.

9. The construction of claim 8 wherein a cap plate is removablyconnected to said frame and is connected to the bearing for the upperdisk to provide for adjustment of such bearing toward and away from saidpass, said cap plate when disconnected from said frame being movablewith the bearing for said upper disk when such hearing is slid upwardlyto disassembled relation with said frame.

10. The construction of claim 9 wherein said bearing for the lower discis adjusted toward said pass by means of an adjustment carried by saidframe but which has only abutting relation with such hearing so as notto hinder disassembling movement thereof.

11. The construction according to claim 1 wherein the stock is movedthrough the pass as a consequence of roll rotation and roll inclination,and further including,

a mandrel disposed within said tubular stock and means for rotating saidmandrel in the same direction and at no less than the rotational speedimparted to said stock by said rolls,

and means for simultaneously advancing said mandrel with said stock atno less than the speed of advance of said stock as it is discharged fromsaid pass.

References Cited UNITED STATES PATENTS 803,079 10/1905 Thust 72961,115,495 11/1914 Brock 72-96 1,946,933 2/1934 Diescher 7296 2,034,2843/1936 Diescher 72-96 LOWELL A. LARSON, Primary Examiner 10 US. Cl. X.R.

